> In January, the drug received what's known as accelerated approval from the FDA, based on its ability to remove the substance beta-amyloid from the brains of people in the early stages of Alzheimer's.
Whenever beta-amyloids come up, I recall that they seem to be quite divisive. Can someone explain to me what the debate is about? The FDA appears to believe that they are a cause of Alzheimer’s based on this drug’s approval
> There seems to be a lot of questionable statistics done.
I doubt it in the sense of "finger on the scale". For some indications (common cold) the statistics are pretty clear (large n, unambiguous signals) even if the therapies are poor (thus there is basically no treatment for the common cold).
Something like Alzheimers is at the other extreme: the disease is very poorly understood, it's very serious, and even measuring progress is difficult. So if you can find something that appears to show some net benefit to a nontrivial proportion of patients it's considered ethical to get it out there.
Sure, the gold standard would be a multi-arm trial with controls, lasting 30-40 years and starting with subjects without any symptoms at all. That's probably the only way to get a reasonable n. But apart from the fat that nobody would, or probably even could, do such a trial, I doubt it would be ethically acceptable.
What causes Alzheimers? Is it beta-amyloids or something else? They have seen some improvements by removing them but the science isn't really clear. Ultimately some benefit is good but we have also seen the cost of these drugs and it's very expensive for little hope.
I think the approval is just that, approving something that has some therapeutic benefit that outweighs the negatives. And something that moves the needle is better than nothing.
Alzheimer's, like most diseases, is described by its symptoms (hence the jargon, "indication"): cognitive impairment accompanied by amyloidosis, a buildup of amyloid plaque in the brain.
Does the plaque cause cognitive impairment? Could it be a prion (I think this question might have been ruled out, but don't follow it). Is the plaque a defense, or consequence of one, mounted by the body? Is the plaque a separate side effect of whatever is causing the cognitive decline?
Nobody knows the answers to these questions. The first one was long thought to be likely but attacking the plaque doesn't seem to have been fruitful.
When you apply for an NDA (basically drug approval) you can specify whatever endpoints you like (e.g. plaque reduction) but the division you apply to will also impose its own requirements (mainly efficacy vs placebo and/or existing therapy, and safety, again vs placebo, existing therapy, and the seriousness of the indication itself).
So the company may have proposed a plaque endpoint (target) but as our lack of understanding of plaque has become clear, they will require a change in impairment rate as a requirement for approval. Because the disease is so serious and options so few they are likely to approve a therapy that shows marginal (but non-zero) improvement in some adequate proportion of the treatment base.
Note: I have never worked on an alzheimer's program, or any neurology program, so this is a generic observation of the approval process.
I am not sure how to feel about this. The drug costs $27k a year.
"In studies reviewed by the FDA, Leqembi appeared to slow declines in memory and thinking by about 27% after 18 months of treatment. It also dramatically reduced the sticky beta-amyloid plaques that tend to build up in the brains of people with Alzheimer's."
There are life-threatening side effects. Although, the diseases is awful itself and I would probably choose death.
However, this drug had an accelerated approval. This makes me a bit uneasy. It signals to drug companies that they can pick any terminal illness, develop a drug for it, show minimal efficacy, and get quick approval even if the side effects are deadly. In the end they profit.
Will this lead to more drugs? Faster scientific research? Or higher profits for the drug companies?
> It signals to drug companies that they can pick any terminal illness, develop a drug for it, show minimal efficacy, and get quick approval even if the side effects are deadly. In the end they profit.
The FDA has already put into place an accelerated approval process for this explicit purpose. The alternative is that rare diseases are too expensive/time-consuming to develop cures for, and drug companies exclusively focus on popular/easy-to-treat illnesses (more so than today).
Neither world is great, but at least we get a better variety of drugs in this world. Open to better ideas still.
I think it's probably fine. It adds options for those who would rather die fighting. The exact placement of the line the FDA draws for approval doesn't align perfectly with everyone's values and situation, so there should be a little wiggle room.
8 comments
[ 3.6 ms ] story [ 34.0 ms ] threadWhenever beta-amyloids come up, I recall that they seem to be quite divisive. Can someone explain to me what the debate is about? The FDA appears to believe that they are a cause of Alzheimer’s based on this drug’s approval
There was a study done that said people who took the drug were slightly better off.
No idea how valid the study was. There seems to be a lot of questionable statistics done.
I doubt it in the sense of "finger on the scale". For some indications (common cold) the statistics are pretty clear (large n, unambiguous signals) even if the therapies are poor (thus there is basically no treatment for the common cold).
Something like Alzheimers is at the other extreme: the disease is very poorly understood, it's very serious, and even measuring progress is difficult. So if you can find something that appears to show some net benefit to a nontrivial proportion of patients it's considered ethical to get it out there.
Sure, the gold standard would be a multi-arm trial with controls, lasting 30-40 years and starting with subjects without any symptoms at all. That's probably the only way to get a reasonable n. But apart from the fat that nobody would, or probably even could, do such a trial, I doubt it would be ethically acceptable.
This is just reality.
I think the approval is just that, approving something that has some therapeutic benefit that outweighs the negatives. And something that moves the needle is better than nothing.
Does the plaque cause cognitive impairment? Could it be a prion (I think this question might have been ruled out, but don't follow it). Is the plaque a defense, or consequence of one, mounted by the body? Is the plaque a separate side effect of whatever is causing the cognitive decline?
Nobody knows the answers to these questions. The first one was long thought to be likely but attacking the plaque doesn't seem to have been fruitful.
When you apply for an NDA (basically drug approval) you can specify whatever endpoints you like (e.g. plaque reduction) but the division you apply to will also impose its own requirements (mainly efficacy vs placebo and/or existing therapy, and safety, again vs placebo, existing therapy, and the seriousness of the indication itself).
So the company may have proposed a plaque endpoint (target) but as our lack of understanding of plaque has become clear, they will require a change in impairment rate as a requirement for approval. Because the disease is so serious and options so few they are likely to approve a therapy that shows marginal (but non-zero) improvement in some adequate proportion of the treatment base.
Note: I have never worked on an alzheimer's program, or any neurology program, so this is a generic observation of the approval process.
"In studies reviewed by the FDA, Leqembi appeared to slow declines in memory and thinking by about 27% after 18 months of treatment. It also dramatically reduced the sticky beta-amyloid plaques that tend to build up in the brains of people with Alzheimer's."
There are life-threatening side effects. Although, the diseases is awful itself and I would probably choose death.
However, this drug had an accelerated approval. This makes me a bit uneasy. It signals to drug companies that they can pick any terminal illness, develop a drug for it, show minimal efficacy, and get quick approval even if the side effects are deadly. In the end they profit.
Will this lead to more drugs? Faster scientific research? Or higher profits for the drug companies?
The FDA has already put into place an accelerated approval process for this explicit purpose. The alternative is that rare diseases are too expensive/time-consuming to develop cures for, and drug companies exclusively focus on popular/easy-to-treat illnesses (more so than today).
Neither world is great, but at least we get a better variety of drugs in this world. Open to better ideas still.